Contents

Understand

It is a good site for varied topography, biodiversity and depth variation.

Position

S34°02.838’ E018°18.316’ (Top of blinder)

South of Duiker Point, below Karbonkelberg

This site is in a Marine Protected Area (2009). A permit is not required.

Name

The area is named "Stonehenge" after a more or less circular ring of rocks which break the surface near a much larger rock which is shown on the charts.

Depth

Maximum depth is over 22m, with an average of about 12m to 15m

Topography

Big boulders and rock outcrops over an extensive area. High relief in deeper areas with swim-throughs, holes and overhangs.

Stonehenge blinder is a huge granite corestone pinnacle about 65m E-W by 45m N-S at base, tapering to 45m E-W by 25m N-S near the top. There is a narrow crack about 1.5m wide and several metres deep by 15 or more metres long near the south east side, and the north side is very sheer. The top point is a bit away from the north eastern edge and is about 3m deep. The bottom is rock at 20m+.

Geology:
Granite of the late Pre-Cambrian Peninsula pluton

Conditions

The site is exposed to south westerly swells, so best when the south west swell component is low and short. This may occur after south easterly winds. The site is usually at it's best in summer, but there may also be occasional opportunities in autumn or early winter.

This is an area which sometimes has upwellings, caused by strong south easterly winds, resulting in cold clear water, and may then have a plankton bloom, which will reduce the visibility again.

Get in

The site is only accessible by boat. It is about 6.5km from Hout Bay harbour.

See

Marine life

Typical of the big reefs of the Atlantic coast. There is a heavy growth of red bait in shallow areas, Kelp on top surfaces in moderate depths, and fairly bare rock with urchins on relatively flat deep surfaces. Walls, overhangs and other steep surfaces are covered with wide variety of sponges, corals, ascidians and other invertebrates.

Photography

Good photographic site. (photographic equipment suggestions)

Routes

Drop in at the pinnacle and descend to the bottom. Slowly ascend as you swim around the pinnacle, observing the various zones. If the sea is calm, a safety stop can be done over the top of the pinnacle.

Stay safe

Hazards

Cold water, Strong surge in gulleys and swim-throughs, and over the top of the shallow parts of the reef. Strong offshore winds may develop over a short time.

Skills

No special skills required. The ability to deploy a DSM and use a compass is useful.

Equipment

A light can be useful to look into dark places and to restore colour at depth. A compass can help keep track of your position, and a DSMB is handy to allow the boat to keep track of ascending divers. Nitrox can extend your no-decompression time if you are well insulated.